Improvement in lifting-jacks



UNITED STATES PATENT OFFICE.

JOHN N. CROSBY, OF NEr YORK, N. Y.

IMPROVEMENT IN LlFTlNG-JACKiS.

Specification forming pait of Letters Patent No. 147,046, dated February 3, 1874; application filed December 5, 1873.

To all whom it may concern:

Be it known that I, Jol-1N N. CROSBY, of New York, in the county of New York and State of New York, have invented certainnew and useful Improvements in Lifting-Jacks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use it, reference being had to the accompanying drawings which form part of this specification, in which- Figure l is a side view, and Fig. 2 a plan view, of my invention.

This invention has relation to lifting-jacks for carriages, &c., and consists in the novel construction and combination of means for the adjustment' of the jack to any desired height, and for locking the lifting-lever when the weight is raised.

eferring to the accompanying drawing, A A' designate a pair of supports or legs, hinged together at their upper ends by means of the curved plates B and hinge-pins I), the former being secured to the sides of the support A'. Vhen the jack is set in position for use, the supports are diverged toward their lower ends, so as to firmly sustain the superinculnbent weight of the axle or other object to which the jack is applied. The supports being hinged together allow the jack to be adjusted to any required or convenient height. The plates B are curved at their upper ends, so as to leave a space between the upper ends of the supports A A' for the passage ot' the lifting-link and the reception of the end of the lever. C designates the lever, provided at one end with the plates d d, which are formed with eyes d', as shown, or in any other equivalent manner, for the reception of, and to allow said lever to work upon, the pivotbolt u, which is secured to the plates B B. The eyes d' enter between the two plates B a slight distance above the end of the support A', as shown. The plates d d extend beyond the end of the lever C and hold a transverse pin, e, upon which is hung a curved link, el, sustaining a chain, e2, and hook e3, or their equivalents.

In using the jack, the supports are first placed in position, and, if the weight be a carriage-body, so as to straddle the axle. The lever is then raised, thereby lowering the chain-link and hook until said hook is attached to the object to be raised, after which the lever is lowered until it touches the support A', in which position, it will be noticed, the pin e lies back of a vertical line intersecting the pivotal bolt n, thus preventing the raising and unlocking of the lever by lthe gravity of the object lifted.

The hook e3 is bent at both ends, and is vertically adjustable upon the chain.

Vhen the jack is no't in use, it may be folded compactly for transportation, &e.

I claim as my inventionl. The combination of the hinged divergin g supports A A', conliecting-plates B, self-locking lever C, and curved link c1, substantially as shown and described.

2. The combination, with the lever O having the projections d', of the support A', fulcruni n, bent link el, and link-support e, substantially as shown, and for the purpose specified.

In testimony that I claim the foregoing I have hereunto set my hand this lst day of December, 1873.

JOHN N. CROSBY.

Witnesses:

JosEPH E. Cnosnv, GEORGE C. HOWELL. 

